The present invention relates in general to dental implants, and in particular to a new and useful dental implant hole guide extension which provides a dentist with an accurate guide to follow for drilling a second and subsequent holes after the critical initial pilot hole for dental implants so that the subsequent holes are aligned on an acceptable axis in the patient's jaw bone, without endangering adjacent teeth.
The present invention is for use with a dental implant hole guide arrangement disclosed in U.S. Pat. No. 5,888,065 issued Mar. 30, 1999 to the inventor of the present application and incorporated here by reference. The dental implant hole guide arrangement of U.S. Pat. No. 5,888,065 allows a dentist to make the critical first hole for an implant without endangering adjacent teeth.
Since 1981, dental root form implants have become a standard procedure for replacing missing teeth. Unlike other dental procedures such as crown and bridge work, root canals and the like, which utilize at least part of the original tooth as a foundation for the tooth replacement, implants require the drilling of holes directly into the bone of the jaw.
Although the dental implants have many benefits, particularly where a patient is missing teeth over large portions of the mouth, various complications can follow implant placement, especially to adjacent teeth. The bone may be overheated during implant surgery for example and this can devitalize an adjacent tooth. Endodontic lesions can also form which compromise the implant fixture by preventing integration of the bone around the fixture (Osseointegration) causing loss of the implant.
Another potentially more serious problem involves traumatic injury to the root of an adjacent tooth which is in the path of the hole drilled for the implant.
The case history of such a traumatic injury can be found in the inventor's article "Tooth Devitalization Via Implant Placement: A Case Report", Sussman, Periodontal Clinical Investigations, Vol. 20, No. 1, 1998, Northeastern Society of Periodontics, pp. 22-24.
U.S. Pat. No. 5,888,065 solves this problem by providing a dental implant hole guide arrangement for use in drilling a pilot hole for a dental implant which has an acceptable axis, the arrangement comprising tooth engagement means for engaging a tooth which is near the site in the patient's mouth for receiving the pilot hole, a fixing mechanism for fixing the engagement means to the tooth so that it does not move readily, and a guide member connected to the tooth engagement means and extending over the site, the guide member having a guide which is aligned with the acceptable axis of the pilot hole and which can be used to guide the movement of a dental bur for drilling the pilot hole.
Another more complex and time consuming technique for properly aligning the initial implant hole for a patient is disclosed in U.S. Pat. No. 5,015,183 entitled LOCATING DEVICE AND METHOD OF PLACING A TOOTH IMPLANT. According to this method, a stent comprising a negative impression of a patient's teeth in the vicinity of the implant is taken. Multiple x-ray opaque strips are placed in the negative impression and an oblique x-ray is taken. This x-ray is. used as a diagnostic tool for the patient's jaw structure to help plot the trajectory of an implant fixture in the jaw.
Once an acceptable initial implant hole is formed in the jaw, subsequent holes can be produced by using the initial hole as a guide. This is when multiple implants are to be installed. See, for example, U.S. Pat. Nos. 5,741,133 and 5,302,122. Other techniques and apparatuses for drilling holes in the jaw bone are disclosed in U.S. Pat. Nos. 4,787,848 and 4,998,881. A need remains, however, for a simple and effective tool which can be used particularly by general dentists to permit them to produce the initial pilot hole along an acceptable axis in a patient's jaw bone. Once the initial bore is made, it can be enlarged to the required final diameter, generally about 4 mm., using ever increasing bur sizes. Once the initial hole is drilled, the enlargements are easily made using the initial hole as the guide. The present invention provides a way of making that critical initial hole.
Fixture positioning guides for guiding a dental drill to make a subsequent implant hole at fixed spacing from a previous one are available from Nobel Biocare AB under the trademark BRANEMARK SYSTEM. The guides include a post which is inserted into the previous hole. A guide block extends laterally of the first hole and a drill can be guided along a concave surface at the end of the block to form the subsequent hole. There is no mechanism in the BRANEMARK SYSTEM for fixing the center on the hole in the buccal/lingual direction however, because the block can rotate freely with the post in the first hole.